Vibration was a bad U joint - Diesel Forum

Skydiver · 12-20-2012, 12:02 PM

I posted the fix for a bad vibration in another thread, but it's buried and I wanted to post separately for anyone doing a search on U joints. I'd had a bad vibration between around 50-60 mph while under load. Took my foot off the accelerator and the vibration stopped immediately. Took the truck to the shop yesterday, had the rear-most U joint replaced and now the vibration is gone.

**klhansen** · 12-20-2012, 03:06 PM

Glad you got it figured out, Scott.

If I had been fighting it that long, I would have had both driveshafts out and checked long ago.

Saw in your post original post that the mechanic that drove it when you initially had the problem said he didn't think it would be u-joints, among other things. I guess he was wrong.

I had a similar vibration (really not that bad, but noticeable) a few years bach on the way back from the drag strip out at Butte. Dropped the rear DS and replaced all 3 joints that night, finding one of them with needle marks on the drive side of the cross. That fixed it up and I was back at the drag strip the next day.

Skydiver · 12-20-2012, 04:04 PM

Two problems/fixes, actually. The first problem (vibration) from a few months ago was fixed when I replaced a bad ESOF hub. Then the newer vibration (U joint) started a few weeks ago and got steadily worse and that's what was fixed yesterday. Yesterday they also put in a new output seal (I believe where the drive shaft goes into the transfer case) where I'd been having a little leak. Like lots of things around here, winter was upon it before I knew what happened.

**klhansen** · 12-20-2012, 10:35 PM

Quote:

Originally Posted by Skydiver

Like lots of things around here, winter was upon it before I knew what happened.

So true.

Fat Diesel · 12-26-2012, 11:29 PM

I just put a one piece aluminum driveshaft on my early 99 CC SB from CCI in Michigan. Pretty nice piece that only weighs 25 pounds. No vibrations after the swap, but in truth rebuilding the stock one would have cured it as well.

Kevin- Still have not needed to use the Injector B.O.B. since I made it from the pdf. Close to 300,000 miles now.

Andy

Mongus · 12-27-2012, 09:39 AM

Well, maybe you guys can help me out.

I just replaced all 3 u joints in my F550 ( spicer made in the USA - grease able ) and the carrier bearing ( Ford OEM )

I have a vibration at 60 mph up that is BAD !
Makes me drive at only 55 -60 mph.....

All new Bridgestone tires ( balanced and centrifical balancers too )

What can it be ??????????????

Thanks !

Note, I only did the replacement because I had the drive shafts powder coated.

I had a vibration before, but that was ( at least I thought ) bad ball joints.

Fat Diesel · 12-27-2012, 11:10 AM

Double check to make sure the u-joint is seated correctly in the rear end pinion, and not slightly off.

**klhansen** · 12-27-2012, 03:03 PM

Did you have the balance checked on the driveshafts? That can cause problems even with new u-joints.

INFRNL · 12-27-2012, 03:37 PM

Quote:

Originally Posted by Mongus

Well, maybe you guys can help me out.

I just replaced all 3 u joints in my F550 ( spicer made in the USA - grease able ) and the carrier bearing ( Ford OEM )

I have a vibration at 60 mph up that is BAD !
Makes me drive at only 55 -60 mph.....

All new Bridgestone tires ( balanced and centrifical balancers too )

What can it be ??????????????

Thanks !

Note, I only did the replacement because I had the drive shafts powder coated.

I had a vibration before, but that was ( at least I thought ) bad ball joints.

I used to have a vibration around 60 and it got worse as I went faster. I had a bad pinion bearing and new tires fixed my issue. Its been some time, but I believe it was actually the tires that really fixed the issue.

Hope you get it figured out.

Mongus · 12-27-2012, 05:46 PM

I did not have the drive shaft balance checked.
Would it go out of balance ?

My tires are a brand new Bridgestones. When I say new, I put the truck back together all at one time.

I had it in my shop for 6 months installing all the mods / new parts I bought. All $7,000 worth,,,,,,,,,,,,,,,,,,,,, love my truck

**klhansen** · 12-27-2012, 07:50 PM

Quote:

Originally Posted by Mongus

I did not have the drive shaft balance checked.
Would it go out of balance ?

It might have if it got dinged by a rock or whatever sometime during it's life. Although if you weren't having problems before the u-joints were replaced, you could probably rule that out.

Hope you get it tracked down.

Oneof6 · 12-28-2012, 07:12 AM

Try to use frequency, speed, to include or elimiate certain groups of parts. Imbalance induces centrifugal force from the unequal distibution of mass / weight rotating around an axis. The defect amplitude produced is a mathmatically predictable curve that, all other things being the same, varies with the square of the speed / frequency increase or decrease. All that really means is the faster it goes more force amplitude the slower the less. That sounds like a so what answer but it gives imbalance characteristics that can be used diagnostically. First thing I would do is elimiate the most common imbalance source on the truck, the tires. Get them balanced on a Hunter balancing machine with the force balancing feature, the go from there. Drive shaft imbalance, that would show at engine rpm frequency not necessarily at vehicle speed or tire rotational frequency. Throttle on or throttle off make a differance in force, seem to be in the front or back?

Mongus · 12-28-2012, 07:05 PM

Thanks for the replies.

Ok, so I think it comes from the rear. ( nothing at all in the steering wheel )

It starts every time at 60 - 62 mph...
And the faster you go, the worse it gets. ( I back off after about 20 - 30 seconds. I don't want to hurt the truck )

I was on the road today for work, 1 hr on highway and 1 hour back home.

I am going to check to make sure nuts and bolts are tight.

Next, I will remove my centrifugal wheel balancers to see if maybe ,,,,,,,,,

I would love to track it down and get rid of this.

Buckbuster · 02-14-2013, 10:07 PM

Quote:

Originally Posted by Skydiver

I posted the fix for a bad vibration in another thread, but it's buried and I wanted to post separately for anyone doing a search on U joints. I'd had a bad vibration between around 50-60 mph while under load. Took my foot off the accelerator and the vibration stopped immediately. Took the truck to the shop yesterday, had the rear-most U joint replaced and now the vibration is gone.

The very same same thing happened to me with my 01 F250. New U joint in back and now smooth riding.

01f25073 · 02-15-2013, 12:38 PM

Speaking from experience: I had a "hopping" vibration under braking from speed. Yet another problem hard for Ford mechanics to diagnose, but I would suppose this isn't that common as higher constant speed vibrations are. When the right driveline tech drove while I rode with him, he said all we can do is replace the driveline. He suggested to take it to a highly regarded driveline shop for repair (which was the best advice he could have given me). So........

If you are having driveline issues OR you replace your driveline, take your ride to a reputable driveline shop for service. If they are good, they will get rid of the non-greaseable u-joints for greaseable ones and balance the shaft. I was told on when I picked up my truck that if I grease the u-joints at every oil change, the driveline will last as long as the truck. Greasing u-joints is SUPER easy, just buy a grease gun with a flexible applicator, and keep tubes of grease. Since this happened, I swapped out ALL u-joints on my truck to greaseable ones for piece of mind.